(1). Field of the Invention
This invention relates to an exhaust manifold for a combustion engine, and more particularly to an exhaust manifold for a combustion engine having a body and several flanges which are separately produced and/or formed and which are thereafter joined to the body and which cooperate with the body to form an exhaust manifold.
(2). Background
Exhaust manifolds are typically connected to the cylinder head or engine block of a combustion engine and receive and collect the various gases produced by the combustion process occurring within each of the engine""s piston-containing chambers or cylinders. Particularly, the manifolds collect the exhaust gases and transfer the gases to an automobile exhaust system.
An engine may include several exhaust manifolds, each of which includes a generally hollow body typically having several integrally formed inlet flanges and one outlet flange. Each of the flanges surround an aperture, integrally formed within the body, which allows for communication with the interior of the hollow body.
Particularly, the inlet flanges are each adapted to be bolted upon the cylinder head or cylinder block and to be sealingly secured to a unique one of the cylinder chambers of the engine, thereby allowing the body apertures and the cylinders to cooperatively and sealingly communicate the waste gases into the interior of the manifold body. The sealing attachment of each of the manifold inlet flanges to the cylinder head is particularly important since a relatively large volume of relatively high temperature gasses typically pass through these manifolds and the emission of these untreated toxic gasses is environmentally undesirable. The unregulated flow of ambient air into the manifold is also undesirable. The outlet flange is also sealingly attached to the automobile exhaust system which normally includes the xe2x80x9cdownpipes,xe2x80x9d catalyst, muffler, and tailpipe. The outlet flange allows for the transfer of the collected waste gases, through a manifold body aperture, to the exhaust system. Because these manifolds collect and transmit relatively high temperature gas, they must have a considerable resistance against thermal stress fractures and fatigue; they must be structurally durable; and all of their sealing attachments must be and must remain very secure.
Usually these manifolds are created and/or formed as a xe2x80x9csingle integral piecexe2x80x9d by the use of a relatively complex and relatively low yielding casting process which creates a relatively large amount of wasted material and which fails to produce the flange portions within certain desired tolerance limits, such as those associated with surface smoothness. Hence, once the manifolds are created, a separate xe2x80x9cmachiningxe2x80x9d or smoothing of each of the manifold flanges is required in order to ensure that the engine contacting surfaces of each of the flanges are relatively smooth and flat, thereby allowing for the secure formation of a sealing attachment of the flanges to the engine. Since the machining of these materials is difficult and time consuming, the overall cost of producing these manifolds is undesirably raised and the concomitant machining waste forms and/or represents undesirable and environmentally toxic waste products which must be eliminated and/or stored.
There is therefore a need to provide an exhaust manifold which is formed by a process which overcomes the various previously delineated drawbacks of the prior art; which reliably and sealingly communicates engine exhaust gases from the various cylinders of the automobile engine to the exhaust system; which has considerable resistance against thermal stress fractures and fatigue; and which requires minimal machining of the created manifold.
It is a first object of the invention to provide an exhaust manifold for a combustion engine which overcomes some or all of the previously delineated drawbacks of prior exhaust manifolds; which has considerable resistance against thermal stress fractures and fatigue; and which sealingly communicates with the cylinders and catalytic converter of a combustion engine.
It is a second object of the invention to provide an exhaust manifold for a combustion engine which includes separately fabricated portions which are later cooperatively joined to form an exhaust manifold.
It is a third object of the present invention to produce an exhaust manifold for a combustion engine which obviates the need to machine the is outlet and inlet flanges after the exhaust manifold is created or formed and which substantially minimizes the machining of the various other fittings and bosses which selectively allow for the flow of air into and out of the manifold.
According to a first aspect of the present invention, an exhaust manifold is provided. The exhaust manifold is made by the process of creating a body portion; creating a plurality of inlet flanges; creating an outlet flange; and joining the plurality of inlet flanges and the outlet flange to the body portion, thereby creating an exhaust manifold.
According to a second aspect of the present invention, a method to create an exhaust manifold is provided. The method includes the steps of forming a body portion of the exhaust manifold; forming at least one inlet flange; forming at least one outlet flange; forming a fitting assembly: and joining the at least one inlet flange, the fitting assembly, and the at least one outlet flange to the body portion, thereby forming an exhaust manifold.
According to a third aspect of the present invention, an automotive component is provided. The automotive component includes a first portion which is created by a first forming process and a second portion created by a second forming process and selectively joined to the first portion.
These and other objects, aspects, features, and advantages of the present invention will become apparent from a consideration of the following specification and the attached drawings.